A four-fold model for subgrouping the hyperkinetic/MBD syndrome.

The major finding of this study is that the presence or absence of aggressive symptomatology differentiates a group of 84 six to twelve year-old Hyperkinetic/MBD boys on a number of important measures at initial referral, during treatment with methylphenidate, and at subsequent five-year-follow-up. When the sample is sorted into high and low aggression groups, several findings emerge which would otherwise have been obscured. Furthermore, there are no significant interactions between aggression (control deficits, negative affect, aggressive interpersonal behavior) and hypertactivity (judgment deficits, hyperactivity, inattention). The value of differentiating between exclusive hyperactivity with aggression) is indicated by the present study.